Gene variant may raise lung cancer risk from radon

NEW YORK (Reuters Health) - Gene variants that lead to decreased amounts of an enzyme known as GSTM1 may raise the risk of lung cancer related to radon exposure, new research suggests. The gene variants also seem to increase the cancer-causing effect of secondhand smoke.

Both radon and secondhand smoke are thought to promote carcinogenesis through the formation of harmful molecules called reactive oxygen species. The enzyme GSTM1 detoxifies these species and their derivatives.

In an earlier study, Dr. Matthew R. Bonner, from the University at Buffalo in New York, and colleagues found that the "GSTM1 null genotype," which is estimated to be carried by 38 percent to 62 percent of Caucasians, increases the risk of lung cancer for never smokers exposed to secondhand smoke.

In the present analysis, the authors sought to confirm this association and look at the effect of this specific genotype on radon-related lung cancer.

The study included data from 270 lung cancer patients drawn from previous case-control studies. Radon levels were determined using long-term alpha-track detectors.

As hypothesized, the presence of the GSTM1 null genotype strengthened the association between radon levels and lung cancer. The interaction between GSTM1 null genotype, secondhand smoke, and lung cancer seen in the researchers' previous study was again confirmed.

"This may be the first study to provide evidence of a GSTM1 and radon interaction in risk of lung cancer," write the researchers.

SOURCE: International Journal of Cancer September 15, 2006.